impedance

What is characteristic impedance?

The RF world is full of esoteric terminology, and not least of these is characteristic impedance, or Z0. Most coaxial cables have a characteristic impedance of 50 or 75 ohms. If you want to know why 50 ohms was arrived at as a sort of standard for radio applications, you can read this post. In […]

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Why 50 ohms?

Coaxial cables, antennas, amplifier inputs and outputs, typically have either a 50 ohm or 75 ohm characteristic impedance. Why? It all comes down to the characteristic impedance value for maximum power transfer being 30 ohms, while the characteristic impedance for theoretical minimum attenuation (loss) is 77.5 ohms. 50 ohms is more or less in the […]

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